1. Field of the Invention
The present invention relates to a traffic monitor system for monitoring traffic in a node of a core network of a communications network.
2. Description of the Related Art
FIG. 21 shows an outline of a core network in a communications network. A core network 11 is a common carrier network and includes: a plurality of edge nodes 121, 122, . . . for connecting (joining or separating) a plurality of ISPs (Internet Service Providers) that are not shown in the attached drawings; and several core nodes 131, 132, . . . for connecting the plurality of edge nodes 121, 122, . . .
For example, assume that a first communications terminal 14 and a second communications terminal 15 communicate with each other through an Internet network. In this case, a packet signal transmitted from the first communications terminal 14 reaches the first edge node 121 through the ISP, reaches the second edge node 122 through the first core node 131, then reaches the second communications terminal 15 through another ISP. It is obvious that another path can be taken when a packet signal is transmitted from the first communications terminal 14 to the second communications terminal 15. For example, after reaching the first edge node 121, the packet signal can be transmitted through second core node 132.
In a communications network that uses packets, such as the Internet, it may be necessary to guarantee a predetermined communication speed by reserving a band for specific communications. To attain this, QOS (Quality Of Service) is utilized as a measurement tool. To guarantee the QOS for specific communications, it is necessary to monitor how a packet is transmitted through a switch or a node in a network.
For example, in a conventional system for monitoring a network, equipment for exchanging IP (Internet protocol) packets collects the data in the packets. Then, the flow of a specific IP packet is obtained by checking the destination IP address and the source IP address from among the collected packets.
In another conventional system for monitoring the network, the interface of the system captures IP packets. The extraction unit extracts a source address, a destination address, etc. from the IP header, transmits them to the analysis unit, and computes the total value of traffic for each path.
The number of packet signals passing through the core network 11 is very large, and the communication speed is as high as several gigabits/seconds or more. Therefore, when attempting to determine the QOS, it is impossible to individually capture the packet signals passing through the core network 11. That is, to designate the path of each packet signal in the edge nodes 121, 122, . . . and core nodes 131, 132, . . . in the core network 11, it is necessary to monitor each packet at a high speed, and individually store the count value of the packets for each route, which cannot be realized with the current resources.
Therefore, in the conventional technology, the guarantee of the QOS for each user or packet flow is omitted, or the size of the core network 11 is increased so that is not needed.
However, in the latter case, since the packet communications develop with a larger capacity at a higher speed, the corresponding facilities are to be extended with sufficient resources, thereby causing the problem of a difficult economic system configuration. Furthermore, the performance in each node of the core network 11 cannot be improved. If the guarantee of the QOS is to be offered, the extensibility of the nodes is correspondingly lowered.